JP2019058914A - Manufacturing method of bottle can - Google Patents

Abstract

To prevent effectively generation of a crack or creases on a tip part of a curl part.SOLUTION: A manufacturing method of a bottle can has a small diameter cylindrical part molding step for forming a small diameter cylindrical part having a smaller diameter than a trunk on an upper part of the trunk, a mouth opening step for bending a tip part of the small diameter cylindrical part toward the radial direction outward, and forming a mouth-opened part enlarged gradually from a bent part toward a tip direction, and a curl step for forming a curl part by folding the small diameter cylindrical part after the mouth opening step, in which, in the curl step, the bent part is formed on an outer periphery lower side bent part, and the mouth-opened part is formed on the curl end.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a method of manufacturing a bottle can having a curled portion to which a metal cap is attached at an opening.

  As a container filled with contents such as a beverage, a curled portion similar to the shape of a bottle is formed at the opening of a bottle-shaped can (bottle can), and at the curled portion, a maxicap (Nippon Closure Co., Ltd. There has been proposed a container which is attached and sealed so as to wrap a skirt portion of a metal cap such as a registered trademark). In this type of bottle can, the shape of the curled portion is important in order to ensure good sealability and openability with the metal cap.

For example, in the container disclosed in Patent Document 1, the bead portion (curled portion) of the opening portion has a first curvature portion connected to the upper end of the mouth main body, a lower outer side than the lower end of the first curvature portion And a ledge extending slightly upwardly inward from the lower end of the outer portion via the second curvature from the lower end of the outer part, and the end of the ledge tapers like a knife edge The tip corner of the end portion is in contact with the outer surface of the mouth body, and is located between the level of the lowest point of the lower surface of the shelf and the level of the substantially lower point of the upper surface of the shelf Is formed. In this container, when forming the curled portion, the position of the tip is specified in detail because the tip generates wrinkles due to the circumferential thickness excess due to the decrease in diameter.
Moreover, in the metal can disclosed in Patent Document 2, the mouth extends straight, and the bead portion (curled portion) formed at the tip of the mouth inclines inward, and the inclination starts The position is set between the lower end portion of the bead portion and the curl start position. Further, the tip end of the curled portion is in contact with the outer peripheral surface of the mouth vertically.

Japanese Utility Model Application Publication No. 58-161843 WO 2007/122971

By the way, when such a curled part is formed, its tip is spread radially outward in the first stage of forming, and is then folded back in the reverse direction from the open end, and finally, in the radial direction The diameter is reduced inward.
As described above, since the tip of the curled part becomes the most severe forming, cracking and wrinkles are likely to occur. In patent document 1, although the device for suppressing a wrinkles is performed, it is not enough.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a manufacturing method capable of effectively preventing the occurrence of cracks and wrinkles at the tip of a curled portion.

  In the method for manufacturing a bottle can according to the present invention, the front end portion is folded outward in the radial direction to form a curled portion at the outer peripheral portion of the mouth portion, and the curled portion is formed at the upper end outer peripheral portion in a folded state. An outer peripheral upper folded portion, an outer peripheral lower bent portion which is bent radially inward at a lower end extending from the outer peripheral upper folded portion, and a curled end extending from the outer peripheral lower bent portion toward the outer peripheral surface of the mouth And forming a small diameter cylindrical portion smaller in diameter than the cylindrical portion on an upper portion of the cylindrical body, and forming a small diameter cylindrical portion at the upper end of the small diameter cylindrical portion. Forming the curled portion by bending the small diameter cylindrical portion after the opening step of forming the opening portion which is bent toward the end and the opening portion gradually expanding in diameter toward the distal end direction from the bent portion; And the curling process, In, the bent portion formed in the outer peripheral lower bent portion, forming the opening widened portion on the curled end.

  The distal end of the small diameter cylindrical portion is bent in advance to form the bent portion and the wide-opened portion, and then the small diameter cylindrical portion is folded back to form the outer peripheral lower side bent portion and the curled end. The processing during the curling process for the lower bent portion and the curled end can be made smaller, and since it is work hardened, the strength against deformation is increased, and the occurrence of cracking and wrinkles during the curling process can be effectively prevented. can do.

  As a preferred embodiment of the method for manufacturing the bottle can, the curling step is performed so as to reduce the radius of curvature of the bent portion formed in the opening step and the rolling step of folding back the small diameter cylindrical portion and the rolling step. It is preferable to have a re-forming step of forming the outer peripheral lower side bending portion and forming the curled end portion continuous with the outer peripheral lower side bending portion by forming.

When a metal cap is attached to the curled portion of this bottle can, the skirt portion of the metal cap is located on the outer peripheral lower side of the curled portion in a state where the seal portion on the inner surface of the metal cap is in close contact from the top of curled portion The inside is sealed by being deformed so as to be rolled in from the outside of the bent portion. Therefore, the outer peripheral surface shape of the curled portion is important in securing the sealing property. Since the curled portion is formed by the large deformation of the metal material, generally, a spring back or the like occurs and it is difficult to secure an accurate outer surface shape.
In this respect, the outer peripheral lower bent portion and the curled end portion have the shape of the majority of the curled portion formed in advance by the mouth spreading step as described above, thereby stabilizing the shape after the rolling step and rolling Since the bent portion is reshaped after the process, the spring back can be corrected, and the outer peripheral surface shape of the curled portion can be finished uniformly and accurately, and good sealing performance can be ensured.

  As a preferred embodiment of the method for manufacturing the bottle can, it is preferable to have a trimming step of trimming the tip end portion of the spread-out portion to make the height uniform between the spread-out step and the curling step.

  The elongation at the time of molding of the metal material has a directionality according to the direction of rolling, and there may be a case where the height of the tip of the wide-mouthed part disperses at circumferential positions. By providing this trimming step, the length of the flared portion, in other words, the length of the curled end portion after the curling step can be stabilized, and the occurrence of cracking and the like can be effectively prevented, and the curled portion Can be accurately formed.

  According to the present invention, since the curled portion is formed by forming the flared portion in advance and then folding it back, it is possible to effectively prevent the occurrence of the crack or wrinkle at the tip end of the curled portion.

It is the front view which made the right half of the container in the embodiment of the present invention the section which passes can axis. It is an expanded sectional view which passes can axis near the curl part of a bottle can after winding up a cap. It is an expanded sectional view which passes can axis near a curl part of a bottle can before tightening a cap. It is a front view of a container. It is a top view of a container. It is a sectional view which passes a can axis explaining processing which winds up a cap on a curl part of a bottle can. About the right half which shows the process until it forms a cup and forms a cylinder among the manufacturing processes of a bottle can, it is the front view made into the cross section which passes a can axis | shaft. It is a flowchart which shows in order the process until formation of a small diameter cylinder part and formation of a curl part among manufacturing processes of a bottle can. FIG. 9 is a front view showing the vicinity of the mouth of the bottle can which changes in the process order of FIG. It is sectional drawing which passes the can axis | shaft which expanded the opening part. It is a side view of a bottle can manufacturing device. It is sectional drawing in alignment with the AA of FIG. It is a cross section through the can axis which shows the state which arranged the mouth spreader tool opposite to the opening end of the middle compact. It is sectional drawing of the direction which passes through the can axis | shaft which shows the state which has given opening processing to the intermediate molded object by the opening tool. It is a cross section through the can axis which shows the state which arranged the rolling tool opposite to the opening end of the middle compact. It is sectional drawing through the can axis | shaft which shows the state which has given the rolling process to the intermediate molded object by the rolling tool. It is sectional drawing through the can axis | shaft which shows the state which has given shaping processing to the intermediate molded object by the shaping tool. It is an enlarged view of the principal part of FIG.

Hereinafter, embodiments of the present invention will be described.
The container 1 consists of a bottle can 10 and a cap 30 attached to the open end thereof, as shown in FIGS. 4 and 5. In the following description, the vertical direction is determined by the direction shown in FIG.
As shown in FIG. 1, the bottle can 10 is made of thin sheet metal of aluminum or aluminum alloy, and is diameter-reduced so as to be bent radially inward at the upper end of the bottomed cylindrical body 11 and the upper end of the body 11 The shoulder portion 12, a tapered cylindrical portion 13 whose diameter gradually decreases upward from the shoulder portion 12 in the can axial direction, and the enlarged diameter portion 14 whose diameter is once enlarged at the upper end portion of the tapered cylindrical portion 13 It has a diameter reducing portion 15 whose diameter is reduced again at the upper end, and a curled portion 16 formed at the upper end of the diameter reducing portion 15. In the bottle can 10, the open end having the curled portion 16 is referred to as a mouth 17.

As shown in FIGS. 2 and 3, the curled portion 16 is parallel to the can axial direction at the upper end of the reduced diameter portion 15 which is inclined at a predetermined angle with respect to the can axial in a longitudinal cross section along the can axial direction. Radially outward from the upper end of the inner peripheral lower side bending portion 21 to be bent, the inner peripheral side cylindrical portion 22 extending along the can axial direction from the inner peripheral lower side bending portion 21, and the upper end of the inner peripheral side cylindrical portion 22 Inner circumferential upper bending portion 23 which bends so as to spread, outer circumferential upper bending portion 25 which is curved with a convex curved surface so as to turn downward from the outer peripheral edge of inner circumferential upper bending portion 23 downward in the can axial direction, outer circumferential upper bending portion An outer peripheral side cylindrical portion 26 extending downward in parallel with the can axial direction from an outer peripheral edge of 25, an outer peripheral lower side bending portion 27 bent radially inward from a lower edge of the outer peripheral side cylindrical portion 26, and an outer peripheral lower side bending portion 27 while reducing the diameter toward a midway position in the can axial direction in the reduced diameter portion 15 And inwardly tapered curled end portion 28 buildings are formed continuously.
Since the curled end 28 extends toward the middle position of the reduced diameter portion 15, the curled portion 16 is formed from the tip end (lower end) of the curled end 28 including the upper end 15a of the upper reduced diameter portion 15 Ru.

  In the curled portion 16 having such a shape, the radius of curvature of the outer circumferential upper turn portion 25 is formed sufficiently larger than the radius of curvature of the inner circumferential upper bent portion 23. For example, as shown in FIG. 3, the radius of curvature of the outer surface is such that the inner peripheral upper bent portion 23 has R1 = 0.5 mm to 2.0 mm, preferably 0.5 mm to 1.0 mm. Moreover, the outer periphery upper side folding part 25 is formed in R2 = 1.5 mm-3.5 mm. If the radius of curvature R2 of the outer peripheral upper side folded portion 25 is larger than 3.5 mm, the sealing performance is reduced, and if smaller than 1.5 mm, there is a possibility that a crack may occur during the curling process or a crack of the paint. The vicinity of the connecting portion between the inner circumferential upper bent portion 23 and the outer circumferential upper turn portion 25 forms a zenith portion 24 disposed at the highest position in the curled portion 16.

  On the other hand, the height position of the outer circumferential lower bent portion 27 in the can axial direction is disposed slightly lower than the height position of the inner circumferential lower bent portion 21 in the can axial direction, but May be In this case, the outer peripheral lower side bending part 27 is formed in R3 = 0.5 mm-1.2 mm by the curvature radius in an outer surface. If the curvature radius R3 of the outer peripheral lower side bent portion 27 is larger than 1.2, the fitting property with the cap is deteriorated, and if smaller than 0.5, there is a possibility that the film may be cracked or the film is broken during the curling process. Further, the curled end 28 extending from the lower end of the outer peripheral lower side bent portion 27 is formed in a substantially straight taper shape, and the angle θ1 formed by the outer surface of the curled end 28 with a horizontal plane orthogonal to the can axial direction is It is set to 0 ° to 45 °. Further, the tip end of the curled end portion 28 is provided so as to substantially abut on the outer surface of the reduced diameter portion 15, and the abutted position thereof is disposed substantially directly below the can axial direction of the zenith portion 24. The length L1 of the curled end portion 28 is preferably 2.0 mm to 4.0 mm. The angle θ2 of the reduced diameter portion 15 with the vertical plane parallel to the can axis is set to, for example, 10 ° to 25 °, preferably 15 ° to 25 °. If the angle θ2 exceeds 25 °, the number of diameter reductions is disadvantageously increased.

  Moreover, although the inner peripheral side cylindrical part 22 and the outer peripheral side cylindrical part 26 are formed concentrically centering on a can axis | shaft, curvature radius R1 of the inner peripheral upper side bending part 23 curvature radius R2 of the outer peripheral upper side curved part 25 Since it is formed smaller, the height in the can axial direction of the inner peripheral side cylindrical portion 22 is formed sufficiently larger than the height in the can axial direction of the outer peripheral side cylindrical portion 26.

For example, the plate thickness of the bottle can 10 is 0.250 mm to 0.500 mm before molding, and 0.200 mm to 0.400 mm at the curled portion 16 in the other dimensions. It is. The outer diameter D of the curled portion 16 is 25 mm to 40 mm, and the width W of the curled portion 16 along the radial direction (the distance from the inner circumferential surface of the inner circumferential cylindrical portion 22 to the outer circumferential surface of the outer circumferential cylindrical portion 26) is 2 .0 mm to 4.5 mm, preferably 3.0 mm to 4.0 mm. The height T of the curled portion 16 (the distance from the upper surface of the zenith portion 24 to the lower end of the curled end portion 28) is 3.0 mm to 5.0 mm, preferably 3.5 mm to 4.5 mm. If the width W of the curled portion 16 exceeds 4.5 mm, there is a risk of cracking during the curling step. If the width W is smaller than 2.0, the shape of the outer circumferential upper side folded portion 25 can not be obtained.

  On the other hand, as shown in FIGS. 4 and 5, the cap 30 is made of a thin sheet metal of aluminum or aluminum alloy, and has a disk-like top surface 31 and a skirt 33 extending vertically downward from the outer peripheral edge of the top surface 31. A tab 34 protruding to extend a part of the lower edge of the skirt portion 33 in the surface direction, and a seal member 35 formed from the inner surface of the top surface portion 31 to the inner surface of the upper end portion of the skirt portion 33 A pair of scores 36 is formed on the outer surface of the top surface portion 31 and the skirt portion 33 from the side edges of the tab 34 at the lower edge of the skirt portion 33 to the skirt portion 33, the bending portion 32, and the top surface portion 31. The tab 34 is formed of a ring portion 37 operated by pinching at the time of opening and a connecting portion 38 connecting between the ring portion 37 and the skirt portion 33, and the connecting portion 38 has a predetermined width and It extends in the direction perpendicular to the lower edge. The ring portion 37 may be formed of a synthetic resin.

  In the example shown in FIGS. 4 and 5, these scores 36 are between the skirt portion 33 and the top surface portion 31 via the skirt portion 33 from both side edges of the connection position of the connection portion 38 of the tab 34 and the skirt portion 33. After passing over the bent portion 32, the top surface portion 31 is formed in an arc shape along the outer periphery, and reaches the skirt portion 33 again via the bent portion 32 at a position beyond half of the top surface portion 31. It is formed in shape. In the top surface portion 31, the score 36 continues in a circular arc shape within a central angle of 90 ° after passing over the bending portion in the top surface portion 31 but is formed only to the middle of the top surface portion 31. In addition to the connection position of the tab 34 to the connection portion 38 of the skirt portion 33, a plurality of slits or scores may be formed.

  The sealing material 35 is formed of, for example, a synthetic resin on the inner surface of the cap 30, and is formed to cover the inner surface of the top surface portion 31. Further, a ridge 39 is formed along the circumferential direction so as to enter the inside of the inner peripheral upper side bending portion 23 of the curled portion 16 when the mouth portion 17 of the bottle can 10 is covered. In the top surface portion 31, the scores 36 are provided at positions radially outward of the ridges 39 of the sealing material 35. Besides the sealing material made of synthetic resin, there are also those coated with a compound.

  In order to manufacture the bottle can 10, first, an aluminum plate material is punched out and drawn to form a shallow cup 40 having a relatively large diameter as shown in FIG. Drawing processing and ironing processing (DI processing) are applied to form a cylindrical body 41 of a predetermined height as shown in FIG. 7 (b), and the upper end thereof is trimmed by trimming. By this DI processing, the bottom of the cylindrical body 41 is formed into a bottom shape as the final bottle can 10.

  Subsequently, the bottle can 10 is manufactured by the bottle can manufacturing apparatus 50 shown in FIGS. 11 and 12. Next, the bottle can manufacturing apparatus 50 will be described. In addition, this bottle can manufacturing apparatus 50 is for processing the cylinder 41 formed as mentioned above into the bottle can 10 of final shape, and the shape of a can changes according to the progress of processing. However, in the following, when the shape of the can is not particularly limited from the cylindrical body 41 to the bottle can 10, the intermediate formed body 42 will be described.

  The bottle can manufacturing apparatus 50 has a work holding portion 51 for horizontally arranging and holding a plurality of intermediate formed bodies 42 in the can axis direction, and a plurality of forming tools 52 for performing various forming processes on the intermediate formed bodies 42. And a driving unit 54 for driving both the holding units 51 and 53. The workpiece holding side of the workpiece holding portion 51 holding the intermediate formed body 42 and the tool holding side of the tool holding portion 53 holding the forming tool 52 are disposed to face each other.

  The work holding portion 51 has a configuration in which a plurality of holding devices 57 for holding the intermediate formed body 42 are annularly arranged along the circumferential direction on the surface of the disk 56 supported by the support shaft 55 facing the tool holding portion 53. It is done. The bottom portion of the intermediate formed body 42 supplied from the supply unit 58 via the supply side star wheel 59 is intermittently transmitted to the holding device 57 by the disc 56 being intermittently rotated by the drive unit 54 about the support shaft 55. They are held one by one and conveyed in the circumferential direction of the disk 56. The intermediate formed body 42 is formed by the forming tools 52 of the tool holding portion 53 during conveyance by the disk 56, and then sequentially discharged to the discharge portion 61 as the bottle can 10 after forming via the discharge side star wheel 60. .

  The tool holding portion 53 has a plurality of various forming tools 52 arranged in a ring along the circumferential direction on the surface of the disk 63 supported by the support shaft 62 facing the workpiece holding portion 51, and the disk 63 is supported by the drive portion 54 It is configured to advance and retract in the axial direction of the shaft 62. The support shaft 62 is coaxially provided inside the support shaft 55.

  In this tool holding portion 53, each processing step such as a plurality of necking types for reducing the diameter (neck-in processing) of the opening of the intermediate formed body 42, and a curled portion forming tool for forming the curled portion 16 A plurality of forming tools 52 are provided to perform processing according to. The forming tools 52 are annularly arranged in the circumferential direction on the disk 63 in the order of steps.

  The intermittent rotation stop position of the workpiece holding portion 51 (disk 56) whose center of rotation is the axis line of the support shaft 55, the can axis of each intermediate formed body 42 whose opening portion faces the tool holding portion 53 side is each forming tool It is set to coincide with the central axis of 52 respectively. Then, by the intermittent rotation of the disk 56 by the drive unit 54, each intermediate formed body 42 is rotationally moved to a position facing each forming tool 52 for the next process, and the processing of the next stage is performed.

  That is, when the tool holding portion 53 advances and the work holding portion 51 and the tool holding portion 53 approach each other, each forming tool 52 performs processing according to each process on the intermediate formed body 42, and both holding portions 51 , 53 are moved away from each other so that the forming tool 52 in the next step faces the respective intermediate formed body 42. As described above, by repeating the operations that the two holding portions 51 and 53 approach and process, separate and rotate, the shoulder 12, the tapered cylindrical portion 13, the enlarged diameter portion 14, and the contraction of the intermediate formed body 42 are contracted. The diameter portion 15 and the curled portion 16 are sequentially formed to form the bottle can 10.

Next, a method of manufacturing the bottle can 10 using the bottle can manufacturing apparatus 50 will be described in the order of steps.
A plurality of forming tools aligned in the circumferential direction of the tool holding portion 53 with respect to the upper end portion of the cylindrical body 41 formed to the state shown in FIG. 7B by drawing and ironing (DI forming) of thin plates such as aluminum alloy While sequentially using 52, the forming tool 52 is moved along the can axis direction to perform the die necking process, thereby reducing the diameter of the upper part from the midway position of the cylindrical body 41 in the height direction to make the shoulder portion 12 After forming the tapered cylindrical portion 13 by gradually reducing the diameter of the upper portion of the shoulder portion 12 and forming the enlarged diameter portion 14 on the tapered cylindrical portion 13, the diameter is reduced again to move upward. A reduced diameter portion 15 is formed to be gradually reduced in diameter in accordance with the above, and a cylindrical small diameter cylindrical portion 18 extending above the reduced diameter portion 15 is formed. FIG. 9A shows a state in which the small diameter cylindrical portion 18 is formed. A series of forming tools 52 for forming the shoulder portion 12 to the small diameter cylindrical portion 18 is referred to as a necking type.

Next, the curled portion 16 is formed on the small diameter cylindrical portion 18. The processing for forming the curled part is as shown in the flowchart in FIG. 8 and in FIG. 9 (a) to (c) sequentially showing the transition of the shape near the mouth due to the processing. And a curling step, which further comprises a rolling step and a re-forming step.
Then, as shown in FIGS. 13 and 14, the forming tool for forming the curled portion 16 is such that the open end portion of the small diameter cylindrical portion in the intermediate formed body 42 formed up to the small diameter cylindrical portion 18 is radially outward. As shown in FIGS. 15 and 16, a rolling tool 75 for bending the small diameter cylindrical portion 18 after the mouth opening is rolled as shown in FIG. 17 and FIG. And a re-forming tool 80 for re-forming the end after being rolled.

  The unrolling tool 70 is a die-necking type tool that moves along the can axis direction to process the intermediate formed body 42 similarly to the above-mentioned necking type, but the rolling tool 75 and the re-forming tool 80 may be Also, the intermediate formed body 42 is formed while being swirled around. As described above, in the bottle can manufacturing apparatus 50, the intermediate formed body 42 is disposed horizontally, and in FIGS. 13 to 18, the can axial direction of the intermediate formed body 42 is disposed in the left-right direction.

  Specifically, as shown in FIGS. 13 and 14, the spread-out tool 70 is formed in a cylindrical shape as a whole, and the outer diameter of the spread-out tool 70 is smaller than that of the proximal end 72. There is. The small diameter tip portion 71 is formed to have an outer diameter slightly smaller than the inner diameter of the small diameter cylindrical portion 18 of the intermediate molded body 42, and can be tightly inserted into the small diameter cylindrical portion 18. Further, a step between the distal end 71 and the proximal end 72 is formed as a tapered portion 73 whose diameter gradually increases from the distal end 71 toward the proximal end 72. Further, a concave arc portion 74 is formed between the rear end of the leading end portion 71 and the leading end of the tapered portion 73. Then, while inserting the tip end portion 71 of the opening spread tool 70 into the small diameter cylindrical portion 18 of the intermediate formed body 42, the tip end of the small diameter cylindrical portion 18 is pressed by the tapered portion 73 in the can axial direction. As shown in FIG. 4, the tip of the small diameter cylindrical portion 18 of the intermediate formed body 42 is spread radially outward along the inclination of the tapered portion 73. As a result of this processing, as shown in FIG. 10, a port widening portion 45 whose diameter gradually increases toward the tip end is formed at the tip end of the small diameter cylindrical portion 18 of the intermediate formed body 42. In the mouth spreader portion 45, a bent portion 46 is formed by the concave arc portion 74 of the mouth spreader tool 70 between the small diameter cylindrical portion 18a remaining after the mouth spreading processing and the mouth spreader portion 45.

The flared portion 45 desirably has a linear tapered shape whose diameter increases toward the tip, and the angle θ3 with respect to the can axis direction is 10 ° to 45 °, preferably 15 ° to 20 °. If the temperature exceeds 45 °, the diameter expansion rate increases, so the risk of cracking increases. Further, the length L2 of the flared portion 45 is substantially equal to the length L1 of the curled end portion 28 of the curled portion 16.
Although it is desirable that the flared portion 45 has a linear tapered shape, it may not necessarily be linear and may be convexly curved toward the can axis of the bottle can 1. By forming the flared portion 45, the shape rigidity of the tip portion can be obtained. Moreover, the impact of the contact between the tip of the intermediate formed body 42 and the mold (the expansion mold) can be reduced during the curling process in the post process. Furthermore, since the diameter expansion ratio of the tip can be substantially reduced by drawing a smaller circular arc at the tip of the curling path during the curling process, it is possible to prevent cracking during curling.
The opening 45 is processed into the curled end 28 of the curled portion 16 as shown by a two-dot chain line in FIG. 10 through a rolling process and a re-forming process described later. Processed into

  In the subsequent trimming process, as shown by the arrow in FIG. 9B, the leading end of the spread-out portion 45 is cut in the horizontal direction orthogonal to the can axis direction. Since the elongation differs in the rolling direction of the aluminum material, in the direction orthogonal to this, and in the direction of 45 ° with respect to these, the tip of the wide-opened portion 45 is slightly wavy, and the wavy portion is removed It is cut at a certain position. However, as described above, the tip of the cylindrical body 41 is trimmed after the DI processing shown in FIG. 7 (b), and the corrugation of the tip caused by the processing from FIG. 7 (b) to FIG. 9 (b) is Since it is to be removed, the cutting allowance in the trimming process in FIG. 9 (b) has a small size.

The rolling tool 75 used in the rolling process is coaxially connected to the rotating body 76 connected to the tip of the rotating shaft (not shown) of the tool holding portion 53 and the rotating body 76, and the small diameter cylindrical portion after opening A rotatable core 77 inserted into the inside of the small diameter cylindrical portion 18a from the open end of the ring 18a, an expanding mold portion 78 pivotally mounted around the core 77 with respect to the rotating body 76, and for folding A mold section 79 is provided. Each of the spreading mold portion 78 and the folding mold portion 79 is formed in a roll shape, and is rotatably supported by the rotating body 76 at a predetermined angle. Moreover, although illustration is abbreviate | omitted, as for the core 77, the outer peripheral part which touches the inner peripheral surface of the small diameter cylinder part 18a is rotatably supported with respect to center part.

Then, in the rolling process, when the tool holding portion 53 is moved forward and the core 77 is inserted into the small diameter cylindrical portion 18a to support the small diameter cylindrical portion 18a from the inside, and the rotor 76 is rotated. While both the mold portion 78 and the folding mold portion 79 turn around the circumferential surface of the small diameter cylindrical portion 18a, the expanding mold portion 78 opens the open end portion of the small diameter cylindrical portion 18a outward, The open end is folded back by the folding mold 79. The open end formed by the rolling tool 70 is referred to as a roll portion 19.
In this rolling step, the cross-sectional shape along the can axis direction of the bent portion 46 to the spouted portion 45 previously formed in the spouting step is reversed as it was formed at the spouting step. Form the lower end of the outer periphery of the

Next, the re-forming tool 80 used in the re-forming step is coaxially connected to a rotating body (not shown) connected to the tip of the tool holding portion 53 and inserted into the roll portion 19 of the intermediate formed body 42 A rotatable core 81, a rotatable roller 82 pivotable about the core 81 and pivotable about a horizontal axis, and a cam mechanism (not shown) for pivoting the roller 82 And). In FIG. 17, the state before the roller 82 of the reforming tool 80 contacts the roll portion 19 (the state shown on the upper side) and the state where the roller 82 is in contact and reformed (the state shown on the lower side) are respectively It represents.
In the roller 82, a forming recess 84 is formed in the outer peripheral portion in the shape of a groove along the circumferential direction, and the forming recess 84 is a cylindrical surface 85 at the deepest portion and an upper end of the cylindrical surface 85 as shown in FIG. A concave curved surface 86 continuing from (the right end in FIG. 18) and a tapered surface 87 having a downward slope from the lower end of the cylindrical surface 85 (the left end in FIG. 18) to the lower (left).
The core 81 continues to the support portion 88 inserted inside the roll portion 19 and the upper end (right end in FIG. 18) of the support portion 88, and the support portion 88 is inserted inside the roll portion 19 And a forming portion 89 for forming the inner peripheral portion of the roll portion 19 when pressed radially inward at 82. Most of the outer peripheral surface of the forming portion 89 is formed on the cylindrical surface 89a along the can axis direction, and the upper end (the right end in FIG. 18) is formed on the concave arc surface 89b.

  Then, in the re-forming step, the main body of the device is moved forward, and the support portion 88 of the core 81 is inserted into the roll portion 19 to support the roll portion 19 from the inside, and the forming portion 89 is the top surface of the roll portion 19 The inner peripheral portion of the roll portion 19 is formed by forming the support portion 88 by displacing the roller 82 radially inward in such a state and pressing the outer peripheral portion of the roll portion 19 by the forming concave portion 84 in that state. The outer circumferential portion of the roll portion 19 is reshaped by the portion 89 and the forming concave portion 84 of the roller 82, and the inner circumferential lower bent portion 21 following the diameter reducing portion 15, the inner circumferential cylindrical portion 22, the inner circumferential An upper bent portion 23, an outer circumferential upper bent portion 25, and an outer circumferential cylindrical portion 26 are formed, and the previously formed bent portion 46 and the wide-opened portion 45 become an outer circumferential lower bent portion 27 and a curled end 28. , The curl part 16 which these continued was formed It is.

  Specifically, the roller portion 19 is pressed so as to be held between the forming portion 89 of the support portion 88 and the forming recess 84 of the roller 82, and the inner cylindrical portion 22 is pressed by the outer peripheral cylindrical surface 89 a of the support portion 88, The inner circumferential upper bent portion 23 is reshaped by the concave arc surface 89 b, and the outer circumferential upper curved portion 25 is reshaped by the outer circumferential cylindrical portion 26 and the concave curved surface 86 by the cylindrical surface 85 of the roller 82. The tapered surface 87 is reshaped so that the curled end portion 28 after the opening 45 is reversed. In this re-forming, since the shape of the majority of the curled portion is roughly formed before the rolling step of the previous step, the machining amount is small in any portion, and the spring after the rolling step is processed It is only to reshape the part returned by the bag. In particular, in the outer peripheral lower side bending portion 27 and the curling end portion 28, the bending portion 46 and the opening portion 45 formed in the opening step reverse as they were in the opening step in the rolling step as described above. However, since the radius of curvature of the bent portion 32 is slightly increased by spring back, in this re-forming process, processing is performed so as to reduce the radius of curvature of the bent portion 32 by pressing by the forming recess 84 and The side bends 27 are formed.

This re-forming step can be easily performed by an operation of pressing the roll portion 19 so as to be interposed in the radial direction between the forming portion 89 of the core 81 and the forming recess 84 of the roller 82, which is easy. In particular, by pressing the roll portion 19 in the radial direction by the cylindrical outer peripheral surface of the forming portion 89 and the cylindrical surface 85 of the forming recess 84, the curling portion 16 is reformed while both cylindrical portions 22 and 26 of the curling portion 16 are reformed. The convex curved surface of the inner circumferential upper bent portion 23 and the outer circumferential upper curved portion 25 can be reshaped.
In addition, the outer peripheral lower side bending portion 27 and the curled end portion 28 secure the shape after the rolling step by securing most of the shapes by the opening step in advance, and the reforming step after the rolling step And the outer peripheral lower side bending portion 27 is re-formed, so that the curling portion 16 can be accurately formed with the various dimensions described above by correcting the spring back, and a curling portion that can ensure good sealing performance 16 can be formed.
In the longitudinal cross section passing through the can axis, the curled end portion 28 may be straight, or may be a convex curve or a concave curve toward the inside of the curled portion 16.

On the other hand, the apparatus for attaching the cap 30 to the bottle can 10 has a pressure block 95 for pressing the top surface 31 of the cap 30 put on the opening 17 of the bottle can 10 from above as shown by the chain line in FIG. A plurality of claws 96 arranged along the circumferential direction, and an elastic member (not shown) urging the tip end portions of the claws 96 radially inward. The claws 96 can widen the distance between the tip end portions in the radial direction larger than the maximum diameter of the curled portion 16, but in the most contracted state, they are formed smaller than the maximum diameter of the curled portion 16.
Then, after the cap 30 is put on the curled portion 16 of the bottle can 10, the pressure member 95 presses the top surface portion 31 from above in the direction of the can axis to compress the seal material 35. The outer circumferential surface of the curled portion 16, that is, the outer circumferential side cylindrical portion 26, the outer circumferential lower bent portion 27, is obtained by pressing down the skirt portion 33 from the middle position in the height direction by pressing the skirt portion 33 radially inward as shown by the arrow. While deforming the skirt portion 33 of the cap 30 so as to follow the curled end portion 28, the lower end portion of the skirt portion 33 is wound so as to hook on the curled end portion 28 of the curled portion 16.

Since the lower end portion of the cap 30 is hooked from the outer peripheral lower side bending portion 27 of the curled portion 16 to the curled end portion 28 when the cap 30 is attached, the curled portion 16 from the top portion 24 to the outer peripheral upper side in particular The seal member 35 adheres firmly to the convex curved surface of the folded back portion 25 and the inside of the bottle can 10 is securely sealed.
Further, since the tip end of the curled end 28 is in contact with the reduced diameter portion 15 almost directly below the zenith portion 24 of the curled portion 16, the load in the can axial direction from the pressure block 95 can be bottled through the reduced diameter portion 15 It can be firmly supported by the body 11 of the can 10. Even if the tip end of the curled end 28 is not in contact with the reduced diameter portion 15, the gap between them is small, so that when the load in the can axial direction from the pressure block 95 acts, the contact occurs. It should just be close.

In addition, since the claw 96 descends while pressing the skirt portion 33 of the cap 30 when the cap 30 is attached, a tensile force acts on the skirt portion 33, and the tensile force acts on the score 36 of the top surface portion 31, Since the score 36 is formed in an arc shape along the outer periphery of the top surface portion 31, the tensile force acts in the direction orthogonal to the extending direction of the score 36, that is, in the direction in which the score 36 is expanded. With respect to such a phenomenon, in this container, since the score 36 is disposed directly above the zenith 24, the pulling force by the claw 96 is supported by the outer peripheral edge of the zenith 24, and the zenith 24 Reaching upward is suppressed. Therefore, breakage of the score 36 is prevented.
In addition, since the outer peripheral side cylindrical part 26 is formed in the outer peripheral part of the curl part 16, and this outer peripheral side cylindrical part 26 is formed in the straight cylindrical surface extended in the can axial direction, In this case, the radial positioning of the curled portion 16 and the cap 30 can be precisely performed, and the score 36 of the cap 30 can be accurately positioned just above the zenith portion 24 of the curled portion 16.

  On the other hand, when the cap 30 is opened, the tab 34 is raised to break the score 36 of the skirt portion 33 as it is, and after crossing over the bent portion 32, the score 36 of the top surface 31 is broken while pulling up the tab 34. When the score 36 of the top surface portion 31 is broken, the center portion of the top surface portion 31 between the two scores 36 is lifted since the score 36 is formed in an arc shape along the outer periphery of the top surface portion 31. The arc-shaped portion is left on the curled portion 16. Then, when the tab 34 is pulled up as it is, both arc-shaped parts are separated from the curled part 16 and the entire cap 30 is separated from the curled part 16. In this series of opening operations, if the arc-shaped portions remaining left and right after breaking the score 36 of the top surface portion 31 are large, a large force is required to separate the arc-shaped portion from the curled portion 16 by the pulling operation of the tab 34 thereafter. Although necessary, since the score 36 is disposed directly above the zenith 24 of the curled portion 16, the width of the arc-shaped portion remaining on the curled portion 16 is also small, and hence the subsequent detachment of the arced portion is also Easy and excellent in openability.

The present invention is not limited to the configuration of the above-described embodiment, and various modifications can be made in the detailed configuration without departing from the spirit of the present invention.
For example, although the forming portion 89 of the core 81 is formed by the outer peripheral cylindrical surface and the concave arc surface in the re-forming step, the inner peripheral portion of the roll portion 19 can be remade only with the outer peripheral cylindrical surface without necessarily having the concave arc surface. You may make it shape | mold.
Moreover, although the bottom end cylindrical cylinder 41 was previously formed as the bottle can, and the opening end was shape | molded, a cylinder shall also contain what does not necessarily have a bottom part, and after forming a curl part The separately formed bottom may be wound and tightened on the body.

DESCRIPTION OF SYMBOLS 1 container 10 bottle can 11 barrel 12 shoulder 13 taper cylinder 14 enlarged diameter 15 reduced diameter 15a upper end 16 curl 17 opening 18 small diameter cylinder 18a small diameter cylinder 19 roll 21 inner peripheral lower bent portion Reference Signs List 22 inner circumferential side cylindrical portion 23 inner circumferential upper bent portion 24 zenith 25 outer circumferential upper bent portion 26 outer circumferential cylindrical portion 27 outer circumferential lower bent portion 28 curled end portion 30 cap 31 top surface portion 32 bent portion 33 skirt portion 34 tab 35 seal Material 36 Score 37 Ring part 38 Connecting part 39 Convex strip 40 Cup 41 Cylinder 42 Intermediate formed body 45 Open part 46 Bend part 50 Bottle can manufacturing device 51 Work holding part 52 Forming tool 53 Tool holding part 54 Drive part 55, 62 Support shaft 56, 63 Disc 57 Holding device 58 Supply part 59 Supply side star wheel 60 Discharge side star wheel 61 Discharge part 70 Opening spread tool 7 DESCRIPTION OF SYMBOLS 1 tip part 72 base end part 73 taper part 74 concave circular arc part 75 rolling tool 76 rotary body 77 core 78 expansion die part 79 return die part 80 reforming tool 81 rotary body 82 core 84 molding concave 85 Cylindrical surface 86 Concave curved surface 87 Tapered surface 88 Support portion 89 Forming portion 89a Outer peripheral cylindrical surface 89b Concave circular arc surface 95 Pressure block 96 Claw

Claims (3)

  The front end is folded outward in the radial direction to form a curled portion on the outer peripheral portion of the mouth, and the curled portion is an outer peripheral upper folded portion formed on the upper outer peripheral portion in a folded state; A manufacturing method of a bottle can having an outer peripheral lower side bending portion which is bent radially inward at a lower end portion extending from the lower portion and a curled end portion extending from the outer peripheral lower side bending portion toward an outer peripheral surface of the opening. Forming a small diameter cylindrical portion having a diameter smaller than that of the trunk in the upper portion of the cylindrical trunk, and bending the tip of the small diameter cylindrical portion radially outward, and the bent portion Forming a widening portion which gradually widens in the direction from the tip toward the tip direction, and curling the small diameter cylindrical portion to form the curled portion after the widening step; In the process, the bent portion is below the outer circumference Forming the bent portion, a manufacturing method of a bottle can which is characterized by forming the opening widened portion on the curled end.   In the curling step, the outer peripheral lower side bending portion is formed by forming a rolling step of turning back the small diameter cylindrical portion, and reducing the curvature radius of the bending portion formed in the opening step after the rolling step. The method for manufacturing a bottle can according to claim 1, further comprising the steps of: forming the curled end portion continuous with the outer peripheral lower bent portion while forming the curled end portion.   The method for manufacturing a bottle can according to claim 1 or 2, further comprising: a trimming step of trimming a tip end portion of the spread portion to make the height uniform between the spread step and the curling step.

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